Pitchometer and grinder mount



C. A. WRIGHT PITCHOMETER AND GRINDER MOUNT June 21, 1960 Filed Sept. 26, 1956 4 Sheets-Sheet 1,

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loa I42 wvewroe CALVIN ALEXANDER WRIGHT June 21, 1960 C. A. WRIGHT PITCHOMETER AND GRINDER MOUNT 4 Sheets-Sheet 2 Filed Sept. 26, 1956 Inn 507M CALVIN ALEXANDER WRIGHT 19770 Imps- C. A. WRIGHT PITCHOMETER AND GRINDER MOUNT June 21, 1960 4 Sheets-Sheet 3 Filed Sept. 26, 1956 I l Hu n71 flu a ll 0 was ln/VEA/T'OR CALVIN ALEXANDER WRIGHT June 21, 1960 c. A. WRIGHT 2,941,301 PITCHOMETER AND GRINDER MOUNT Filed Sept. 26, 1956 4 Sheets-Sheet 4 INVENTUR CALVIN ALEXANDER WRIGHT on the lines 66 and 77 United States Patent PITCHOIVIETER AND GRINDER MOUNT Calvin Alexander Wright, 470 Sturdee St., Victoria, British Columbia, Canada Filed Sept. 26, 1956, Ser. No. 612,201

15 Claims. (Cl. 33-174) This invention relates to apparatus which may be used as a pitchometer and/or a grinder mount for checking and correcting propellers.

An object of the present invention is the provision of apparatus for moving a holder transversely across the surface of a propeller blade along an arc, the centre of curvature of which coincides with the centre of the propeller.

Another object is the provision of a pitchometer and grinder mount which may be used to check and correct a part of the surface of a propeller blade either transversely or longitudinally thereof.

Another object is the provision of a pitchometer and grinder mount that may be used on a propeller while the latter is still mounted on its propeller shaft, or upon a dismounted propeller.

As is well-known, each blade of a propeller is twisted relative to the general plane of the propeller so that the surface of the blade extends transversely thereof at an angle to said plane. This angle may be constant throughout the length of the blade, or it may vary at different points throughout that length. In addition to this, the blades may project outwardly substantially at right angles to the propeller hub, or they may be inclined to said hub. As there are numerous different angles to be checked and corrected in a propeller, it has in the past not been possible to do the checking and correcting with one instrument only. In fact, it has not been possible to use the known pitchometers for both checking and grinding purposes.

A pitchometer and grinder mount according to this invention comprises essentially a base to be mounted on the end of a propeller hub, an elongated support mounted on and extending outwardly from the base, said sup- ,port when the base is mounted on a hub extending parallel to the hub axis, a carriage mounted on the support for movement longitudinallythereof, a cross arm slidably mounted for lengthwise movement on the carriage and extending generally across the support, a holder connected to an end of the arm and extending substantially parallel with the support, and means on the carriage for retaining the latter in different positions on the support. The holder may carry a pitch rod for checking a propeller blade, or a grinder for correcting the pitch.

An example of this invention is illustrated in the accompanying drawings, in which,

Figure 1 is an elevation of a pitchometer and grinder mount positioned on a dismounted propeller,

Figure 2 is a plan view of the apparatus shown in Figure 1,

. 'Figure 3 is an enlarged vertical section taken on the line 3-3 of Figure 1,

. Figure 4 is a cross section taken on the line 4-4 .of Figure 3, V

I Figure 5 is a vertical section taken on the line 5-5 of Figure 1,

Figures 6 and 7 are vertical sections taken respectively of Figure 1,

Figure 8 is an enlarged section taken on the line 8-8 of Figure 2,

Figure 9 is an enlarged section taken on the line 99' of Figure l,

Figure 10 is a section taken through a blade of the propeller on line 10-10 of Figure 1, t

Figure 11 is a vertical section taken on the line 11-11 of Figure 7,

Figure 12 is a side elevation of a mounting used when this device is applied to a propeller that has not been dismounted from its propeller shaft,

Figure 13 is an end elevation of the mounting shown in Figure 12, with parts thereof broken away,

Figure 14 is a side elevation of a grinder carried by the holder, and

Figure 15 is an end elevation of the grinder.

Referring to the'drawings, 10 is a standard propeller consisting of a hub 11 with a plurality of blades 12 radiating therefrom. Each blade has a surface 13 extending transversely thereof from its leading edge 14 to its trailing edge 15, and this surface is inclined to the general plane of the propeller, and the angle of inclination de-' termines the pitch of the propeller. If desired, each blade may extend rearwardly at an angle to the general propeller plane in the direction of the after end 17 of the hub. The hub has a bore 19 extending therethrough, and said bore tapers or is reduced in diameter towards the end 17 of the hub, see Figures 1 and 3.

The pitchometer and grinder mount is generally designated by the numeral 25. When in use, this device is mounted on the after end 17 of the propeller hub either when the propeller is dismounted or when it is still mounted on its shaft. Figures 1, 2 and 3 show propeller 10 dismounted and resting on the. forward end of the hub. so that it generallylies in a horizontal plane, and the pitchometer projects upwardly therefrom.

Figure 3 shows a mounting 28 by means of which the pitchometer may be secured to hub 11. This mounting consists of a central block 30 having a plurality of elongated recesses 31 opening out from the sides thereof, each recess having a curved bottom 32. A blade 34 .is mounted in and projects outwardly from each recess, and has a curved bottom 35 resting on the recess bottom 32. A spring 37 extending through holes 38 in the blades draws the latter into their respective recesses. Block 30 has a neck 40 projecting upwardly from the upper end thereof slidably extending through an opening 41 in a mounting plate 42, said 43 on its outer face. A pin 44 projects upwardly from the block and slidably through a hole in the mounting plate and its projection 43 in order to keep the block from turning. A comparatively long bolt 46 extends into neck 40 and is threaded into the upper end of block 30.

When block 30 is drawn upwardly of the hub bore '19 by bolt 46 in a manner hereinafter described, the curved bottoms 32 of recesses 31 force blades 34 outwardly against the tension of spring 37, said blades bearing against the bore wall firmly to hold the mounting plate on the after end 17 of the hub.

The pitchometer 25 includes generally a base 50, an elongated support 52 mounted on and projecting outwardly from the base in a lengthwise direction, a carriage 56 mounted on the support for movement longitudinally thereof, a cross arm 59 slidably mounted for lengthwise movement on the carriage, a holder 63 connected to an end of the cross arm, and a guide bar 66 supported near the cross arm and extending generally across the latter at an angle thereto. It is desirable to be able to rotate the cross arm 59 relative to the propeller 10 upon which the apparatus is mounted, and this may be done by making carriage 56 rotatable plate having a circular projection 3 port 52, but it is preferable to rotate the support around the longitudinal axis of base 50 which coincides with the axis of hub 11 upon which said base is mounted.

' Base-50 has a plurality of legs 7 projecting downwardly therefrom near the edge thereof, these legs being spaced apart sufiiciently to fit nicely over projection '43 of the mounting plate. If desired, one or more of the legs may beprovided with a vertical adjusting screw 71 which may be turned to project downwardly from its leg. This screw is used to level the base-should the mounting plate 42 be not quite level when it is drawn against the end of hub 11;

Bolt 46 extends through a central hole 73 through base 50, and when the bolt is threaded into the upper end of block 30 and tightened down, it securely holds the base against the mounting plate and, at the same time, tightens mounting 28 within the hub bore.

' As previously stated, the elongated support 52 is mounted on and projects outwardly from base 50, and it is preferably mounted to rotate around the longitudinal axis of the base. Although the support may be .positioned on the axis, it is preferable to off-set it to one side thereof, as clearly shown at 76 in Figure 3. A sleeve 78 is rotatably mounted on the base over bolt 46, and in this example, the sleeve is mounted in bearings 79 supported within a cup-like holder 80 projecting outwardly from the base. The sleeve permits access to the head of bolt 46 by means of a socket wrench or the like, and it has a head 82 on its outer end upon which the support 52 is mounted to one side of the sleeve axis which coin cides with that of base 50 and hub 11.

Support 52 may be of any desired formation, but it is preferably formed of tubing which is triangular in cross section, as shown at 84 in Figure 2,. said tube having parallel edges 85, 86 and 87. The elongated support is preferably in tubular form for the sake of lightness, and it may have many lightening holes therein, but these have not been shown in order to create confusion in the drawings.

Carriage 56 is slidably mounted on support 52 for movement longitudinally thereof in any desired manner. In this example, the carriage is provided with pairs of wheels 90 and 91 on opposite sides thereof having grooves in the peripheries thereof, wheels 90 riding along the edge 85, and wheels'91 ridingalong theedge 86 of support 52, see Figures 1, 2, 6 and 7.

'Cross arm 59 is slidably mounted for lengthwise movement on carriage 56 in any convenient manner. This may be done by means of a flat bracket 95- secured to the outer face of the carriage by means of bolts 96. As it is desirable to be able to adjust the bracket relative to the'car'riage, these bolts may extend through slots 97 in the carriage, see Figures 7 and 11, and are threaded into a ring 98 on the opposite side of the carriage. When these bolts are loosened, the bracket. 95 may be swu'ng relative to the carriage.

Bracket 95 has upper and lower pairs of off-set legs 100 and 101 at its upper and lower corners, respectively. Legs 100 carry grooved wheels 103, while legs 101 carry grooved wheels 104.

Cross arm 59 is preferably 1n tubular form and of diamond-shaped cross section, see Figures 6 and 7, and

has upper and lower edges 107 and 108 upon which wheels 103 and 104, respectively, ride. The cross arm is preferably of tubular form for lightness of construction, and it may have many lightening holes cut therein, but these have not been shown in order to avoid confusion.

-It is preferable to make the cross arm 59 extensible.

For this purpose, an extension rod 112 extends through the arm andprojects from the end 113 thereof. 'This r'od may slidably extend through a friction bearing 114 positioned within the tube near the end 113, see Figure l.

, The elongated guide 66 is mounted near arm 59 in any desired manner. In this example, a supporting arm *stantially parallel near the indicator.

Y shoulder 164 having .10, as shown in Figures land 2, it is ready for 118 has a split collar 119 at one end thereof, said collar being adapted to fit around the holder of base 50, and it may be tightened on said holder by means of a bolt 120. The supporting arm projects outwardly from the base and has a standard 122 projecting upwardly from its outer end. A pin 124 rotatably extends through a bearing 125 at the upper end of the standard, and at its inner end is fixedly secured to a plate 127 having a curved lower edge 128 along which are graduations 129. The curved edge of this :plate extends through a bracket 131 mounted on the standard near the lower end thereof, and a set screw 132 threaded through the standard is adapted to press the plate against the bracket to hold said plate in any adjusted position. This bracket has an indicator mark 133 on its inner surface, see Figure 5, which is used in relation to the graduations 129. The elongated guide 66 is secured to plate 127 substantially midway between its ends and at the pivot point 124 of the plate. The guide bar may be straight, but it is preferably curved, as clearly shown in Figures 1 and 2, with its centre ofcurvature' coinciding with the longitudinal axis of base 50. Stops are provided at the ends of the guide bar, and these may be in the form of bent pins 135 projecting fromthe bar ends and forming pockets 136.

Guide 66 may be swung to different angular positions by turning pin 124, and the setting of the guide may be read ong'raduations 129 of plate 127. Set screw 132 is tightened to hold the plate and, consequently, the guide bar in any adjusted position.

The 'end 139 of cross bar 59 may rest directly on guide 66 in order to hold carriage 56 up on support 52. However, it is preferable to provide a bearing in the form of a roller 142 which rides on the upper edge of :the guide bar. This bearing roller is connected to the carriage in any convenient manner. In this example, the roller is mounted on the horizontal portion of an L- shaped rod 144, the vertical portion of which extends through and is secured to lugs 145 projectingfrom an end of the carriage, see Figures 1 and 2. The iorizontal portion of this rod projects outwardly from the carriage substantially horizontally with the cross arm 59, as clearly shown in Figure 2. When bearing 142 rests on guide 66, the carriageis supported on the support 52. If the support is rotated around the axis of base 50, roller 142 rides along the guide bar to raise or lower the carriage depending upon the setting of the bar and the direction of movement of the roller.

Holder-63 is preferably in the form of a tube adjustably secured to the outer end of rod 112 by means of a clamping arrangement-150, and extends downwardly subwith support 52. A pitch rod 154 slidably extends from the lower end of the holder tube, and is held in any adjusted position by means of a set screw 155. The tube may have a vertical slot 157 spaced a little above the lower end thereof through which an indicator 158 on the pitch rod may be seen, and graduations 159 are provided on theholder tube along this slot When the device is in operation, screw is loosened to allow pitch rod 154 to ride on the surface 13 of the blade 12 therebeneath, and indicator 158 shows any variations in this surface.

If desired, base 50 maybe provided with a bevelled graduations thereon. Similarly, carriage 59 may have graduations 168 on an end thereof, see Figure 6, which are opposite an indicator mark 169 on bracket 95.

When the pitchometer '25 is mounted on propelli;

use. it is desired to check to see whether certain corresponding points in the four blades are exactly at 90 to each other, pitchometer rod 154 maybe set over the desired point on one blade. Then the supporting arm is rotated through 90 successively for the other three blades.

When it is desired to check the pitch of each blade,

guide 66 is set at an angle that corresponds with the desired. pitch. Then cross arm 59 is swung back and forth around the axis of base 50. It will be noted that the arm actually extends across this axis, in other words, it is directly above the axis of hub 11. As the arm turns, bearing 142 rides along the angular surface of guide 66, causing carriage 56 to move up and down support 52, depending upon the direction of movement of the bearing. At this time, the pitch rod is loose in the holder and if there are any variations in the surface 13 of the blade, these are shown by indicator 158 moving up or down in holder 63. The pitch rod moves across the blade surface along an arc, the centre of which coincides with the longitudinal axis of hub 11. Arm 59 may be moved across the carriage in order that this process may be repeated at different points or stations throughout the length of the blade, and the angle of guide 66 may be changed for each point or station.

Figures 12 and 13 disclose a mounting arrangement for securing the pitchometer 25 on to a propeller hub 170 when said propeller is still on its propeller shaft 171. The propeller is held on the shaft by a large nut 173 in the usual manner, and-the shaft has a tapped hole 175 in the end thereof. A mounting plate 177 has a spigot 178 projecting from a surface thereof, anda central hole 179 extends through the spigot and plate. The mounting plate is spaced from and connected to a base plate 182 by means of a plurality of bolts 183 which extend through the former and are threaded into the latter, each bolt having a spacing sleeve 184 thereon. Plate 182 has a large hole 186 therethrough centrally thereof through which nut 173 may project.

When it is desired to mount the pitchometer, base plate 182 is placed over nut 173 and against the after end of hub 170. Then base 50 is placed over spigot 178, and bolt 46 is moved through hole 179 and turned into the tapped hole 175 of the propeller shaft. When the bolt is tightened down, the pitchometer is firmly held against the mounting .plate and the latter is held in 'posi tion over the end of the propeller shaft and hub. The pitchometer is then erated in the manner described above.

When it is desired to grind the surface of the propeller blade to the required shape, a grinder is substituted for the pitch rod in holder 63.

Figures 14 and 15 illustrate a standard grinder 184 having a grinding disc 185 as it is used with the pitchometer. The grinder is pivotally secured to a yoke 187 by means of studs 188, and the upper end of the yoke has a rod 180 projecting outwardly therefrom which is adapted slidably to fit into holder 63, screw 155 being tightened to hold the grinder in place. An adjustable brace 192 is pivotally connected at 193 to the grinder and at 194 to the yoke. The brace is made in two sections which may be moved relative to each other to adjust the length of the brace, and these are held in any adjusted position by a screw 196.

Figure 14 shows grinder 184 suspended above the pro peller blade 12 with part of its grinding disc contacting the surface 13 thereof. It is obvious that when guide bar 66 is set at the desired angle, arm 59 may be swung around the propeller axis to cause the grinding disc to move transversely across the blade surface in an arc. When the apparatus is set properly, the grinder will remove any high spots on the blade surface during its travel over said surface.

What I claim as my invention is:

1. A pitchometer and grinder mount comprising a base to be mounted on the end of a propeller hub, an axially rotatable elongated support mounted on and extending outwardly from the base, said support when the base is mounted on a hub extending parallel to the hub axis, a carriage mounted on the support for movement longitudinally thereof a bracket mounted on the carriage for rotation around an axis normal to the support, means .adjustably securing the bracket to the carriage, a cross .6 arm slidably mounted for lengthwise movement on the carriage bracket and extending generally across the support said arm being tipped relative to the support when the bracket is so tipped, a holder connected to an end of the armand extending substantially parallel with the support, adjustable guide means carried by the base near the carriage, and means connected to the carriage engaging the guide means, said guide means determining the position of the carriage on the support throughout the length of the latter.

2. A pitchometer and grinder mount as claimed in claim 1 in which the elongated support is mounted on the base for movement around the axis of the hub on whichsaid base is positioned, and the cross arm is so mounted on the elongated support as to extend across said hub axis. Y I

3. A pitchometer and grinder mount as claimed in claim 1 in which the base has an axis to coincide with the axis of the hub upon which it is positioned, and the elongated support is offset relative to the base axis and is mounted on the base for movement around the latter axis, said cross arm extending across the base axis to permit the holder to connect thereto to be moved therewith inwardly and outwardly towards and from the base axis directly in line therewith.

4. A pitchometer and grinder mount comprising a base to be mounted on the end of a propeller hub, said base having an axis extending parallel. to the axis of a hub on which it is mounted, an elongated support mounted on and extending outwardly from the base, said support when the base is mounted on a hub extending parallel to the base axis and-being rotatable around said axis, a carriage mounted on the support for movement longitudinally and axially thereof, a cross arm slidably mounted for lengthwise movement on the carriage and extending generally across the support, a holder connected to an end of the arm and extending substantially parallel with the support, a supporting arm movably mounted on the base and radiating from the axis thereof, said supporting arm being movable around the base axis, an elongated guide mounted on the supporting arm near the cross arm and extending generally across the latter at an angle thereto, and means connected to the carriage and engaging the guide for causing the carriage to move along the support when the cross arm is swung to rotate the support around the base axis.

5. A pitchometer and grinder mount as claimed in claim 4 including means for changing the angle of the guide relative to the cross arm.

6. A pitchometer and grinder mount as claimed in claim 4 including means for adjusting the angle of the cross arm to the support.

7. A pitchometer and grinder mount as claimed in claim 4 in which the cross arm is extensible.

8. A pitchometer and grinder mount as claimed in claim 4 including a stop at each end of the guide for limiting the swinging movement of the arm.

9. A pitchometer and grinder mount comprising a base to be mounted on the end of a propeller hub, said base having an axis extending parallel to the axis of a hub on Which it is mounted, an elongated support mounted on and extending outwardly from the base, said support when the base is mounted on a hub extending parallel to the base axis and being rotatable around said axis a carriage mounted on the support for movement longitudinally thereof, a bracket mounted on the carriage for rotation around an axis normal to the support, means adjustably securing the bracket to the carriage, a cross arm slidably mounted for lengthwise movement on the carriage bracket and extending generally across the support, a holder connected to an end of the arm and extending substantially parallel with the support, a supporting arm extending outwardly from the base transversely of the axis thereof, an elongated guide carried by the supporting arm near the cross arm and extending generally across the latter at an angle thereto, and means connected to "the earria'ge and engaging-the 'gnideior :causing ithe carriag'e 'to move -"along the support whenthe "cross arm is swun to'rotate the su portraromrd i'the base axis.

10. 1A pitehonreter and (grinder mount as :claimed :in

elalim9 in which the guid'e'is rotatable on the supporting arm so that its angle to the cross arm may :be changed, andlincluding means for retaining the guide in different angular po'sitions relative to the arm. 11. -JA lpitehomete'r and grinder mount as claimed in claim 10 in which the supporting arm is'movably mounted on the base for movement aroundt-the latter, and includihg means for retaining said supporting arm in different positions :on the-base.

12. -=pit'ohometer and :grinder mount :comprising a base' to be mounted on the end of a propeller hub, :said base having an axis extending parallel to the axis of a hub o'n which it is mounted, an elongated support mountedbn and extendingoutwardly-irom thebase, said support when the base is mounted on a hub extending p'a'r-allel to the base axis and being rotatable around .said 'axis a car'riage mounted on the support for movement longitudinally and a'xially t he'reof a cross arm slidably mounted tor lengthwise movement on the carriage and extenflinggenerallyacross-the support, a holder connected to an end of the arm and extendingsubstantially parallel with the su'pport, a-fsupp'orting farm movably "mounted Y on the base and radiating from the axis thereof, said sup- 'porting *arm being r-movable around the base axis, an elongated 'guide mounted on the supporting arm-near the eros's' arm and extending generally across the latter at an angle thereto, and a bearing connected to 'the carriage and riding-on'the'guide, whereby the guide causes the carriage tomove alongthe'support'when'thearm is swung to rotate th'e'support around the base axis.

13. -A pitehometer and grinder mount as claimed in :claim l 2 inwhieh the guideisrotatably supported so that th'e angle thereo't to the cross armmay be changed, and including means for're'taining the-guide'in diiferentangular positions relative to the cross arm.

1 4. 'A pitchometer and grinder mount as claimed in elaim lz including .a stopp'oeket .at each end of the guide for limiting the swinging movement of the ":15. pitchometer and grinder mount comprising a base I0 be mounted on the end of a propeller .hub,.means on the baseand extending into the hub for zaligningan axis- 0f the base Withthe hub axis, an elongatedsupport mounted'on and extending outwardly from the base, said support when the base is mountedonahub extending parallelto the base a-xis and being rotatable around said axis, acarriage mounted on the support for movement longitudinally and axially thereof, a cross arm slidably mounted for lengthwise movement on the carriage and extending generally across the support, a holder :connected to an end 'of the arm and extending substantially parallel with the support, a's lpporting arm movably mounted onthe base -andradiating zErom-the axis thereof, said supportingarm beingunovable-around the base'axis, an elongated guide mounted on the supporting arm near the Cross arm and extending generally across the latter at an'angle thereto, and means conneeted'to the carriage and engaging the guide'for causing the carriage to move along'the support when the cross arm is swung to rotate the support around the base axis.

References Cited inthe file of this patent UNITED STATES PATENTS 

